Electrical systems for road vehicles

ABSTRACT

An electrical system for a road vehicle has a pair of electrical loads and a pair of switches controlling the loads, together with a pair of feed lines. One switch makes one feed line positive with respect to the other and the other switch makes said one feed line negative with respect to the other. Polarity sensitive switching means are then provided for controlling the loads when the switches are operated.

United States Patent Holt 1' Mar. 28, 1972 [54] ELECTRICAL SYSTEMS FOR ROAD [56] References Cited VEHICLES UNITED STATES PATENTS t: Willi D idHltCl ,E i d [72] or m W o o an 3,475,585 10/1969 Pierce ..307/38 x [73] Assignee: Joseph Lucas (Industries) Limited, Birmmgham England Primary Examiner-Herman J. l'lohauser [22] Filed; Apt 2 70 Attorney-Holman & Stem 211 App]. No.: 30,562 57] ABSTRACT An electrical system for a road vehicle has a pair of electrical [30] Foreign Application Priority Dam loads and a pair of switches controlling the loads, together July 28, 1969 Great Britain ..37,708/69 with a pair of feed lines. One switch makes one feed line positive with respect to the other and the other switch makes said [52] US. Cl. ..307/ 10 R one feed line negative with respect to the other. Polarity sensi- [51 1 int. Cl. ..H02g 3/00 five switching means are then provided for controlling the [58] Field Of Search ..307/10, 127, 138, 38, 9, 39, loads when the witches are operated,

307/l1,i5,i2,i3, 16,17

2 Claims, 1 Drawing Figure 21 b c L H 43 MW WUIH 1 a c 44 I 44 44 I 45 J 6 I a i b a 2i 21 F 21 El C l i iS i9 49 a go /22 /gg g es 2 PATENTEDMARZB I972 INVENTOR Mal/m 9%! M ELECTRICAL SYSTEMS FOR ROAD VEHICLES This invention relates to electrical systems for road vehicles. An electrical system according to the invention includes a pair of electrical loads, a pair of switches controlling the loads 5 respectively, a pair of feed lines, means whereby closingof one switch makes one feed line positive with respect to the other feed line, and closing of the other switch makes said one feed line negative with respect to the other feed line, and polarity sensitive switching means operable by a pulse 1 between the feed lines for switching the loads on and off under the control of said switches.

The accompanying drawing is a circuit diagram illustrating one example of the invention.

Referring to the drawing, a positive supply line 11 energized by the battery 10 of a vehicle is connected to a plurality of contacts 12a, 12b, 12c, l2i, which are so connected that when all the contacts are in their off position they are all in series but when any of the contacts 12b is moved from its ofi position shown to its on position, the circuit is to the remaining contacts is broken. A negative supply line 13 (conveniently earthed as shown) is similarly connected to a set of contacts 14a, 14b, 14c l4i, the contacts 120 and 14a forming a double pole spring return switch, and the other pairs of 2 contacts with the same suffix forming further double pole spring return switches.

The vehicle further includes a plurality of feed lines 15, 16, l7, 18 which are connected to the double pole switches in various combinations. Thus, closing of the switch 12a, 14a 3 makes the line 15 positive with respect to the line 16, whilst closing of the switch 12b, 14b makes the line 16 positive with respect to the line 15. The other switches energize the lines in various combinations, and it will be noted that each pair of feed lines is energized in response to two different double pole 3 switches, but with a difference in polarity. Using four feed lines as shown, 12 combinations are possible in general, for n feed lines the number of loads that can be controlled is the number of permutations of 2 from n.

Connected across various pairs of feed lines are relay coils 4 19a, 19b, 19c 191 in series with diodes 21a, 21b, 21c 21: g respectively. The arrangement is such that when any one of the double pole switches is closed, one only of the relay coils is energized. Thus, closing of the switch 124, 14a energizes the lines l5, 16, to which the relay coils 19a and 19b are con- 4 nected. However, because of the diodes 21a, 21b, only the coil 19a is energized. Likewise, closure of the switch 12b, 14b energizes only the coil 19b.

The relay coils control contacts 22a, 22b, 22c 22: connected in series with loads 23a, 23b, 23c 23: across the battery 10 by way of a positive supply line 20. All the relays are latching relays, and so when a double pole switch is closed momentarily, its load is energized and stays energized when the switch is returned to its normal position. Operation of the same double pole switch a second time then operates the same relay again to de-energize the appropriate load.

Having thus described my invention what I claim as new and desire to secure by Letters Patent is:

l. A vehicle electrical system comprising in combination n feed lines, a plurality of loads to be controlled, a plurality of switch means, one for each load, means coupling one of said switch means to one pair of said feed lines whereby operation of said one switch means makes one of said pair of feed lines positive with respect to the other of said pair of feed lines, means coupling a second of said switch means to said one pair of feed lines whereby operation of said second switch means makes said other of said pair of feed lines positive with respect to said one of said pair of feed lines, means coupling the remaining switch means to the feed lines so that each switch means energizes two feed lines in a unique manner, and polarity sensitive switching means operable by energization of the supply lines for switching the loads on and off under the control of the switch means, the maximum number of load controllable by the system-being the number of permutations of 2 from n.

2. A vehicle electrical system, including a pair of electrical loads, a pair of switches controlling the loads respectively, a pair of feed lines, means whereby closing of one switch makes one feed line positive with respect to the other feed line, and closing of the other switch makes said one feed line negative with respect to the other feed line, and polarity sensitive switching means operable by a pulse between the feed lines for switching the loads on and off under the control of said switches, said switching means comprising a pair of latching relays successive actuations which energize and de-energize the respective loads, each relay having a coil connected across the feed lines, and the required polarity sensitivity being provided by a pair of diodes coupling the coils respectively to the feed lines.

I l l l 

1. A vehicle electrical system comprising in combination n feed lines, a plurality of loads to be controlled, a plurality of switch means, one for each load, means coupling one of said switch means to one pair of said feed lines whereby operation of said one switch means makes one of said pair of feed lines positive with respect to the other of said pair of feed lines, means coupling a second of said switch means to said one pair of feed lines whereby operation of said second switch means makes said other of said pair of feed lines positive with respect to said one of said pair of feed lines, means coupling the remaining switch means to the feed lines so that each switch means energizes two feed lines in a unique manner, and polarity sensitive switching means operable by energization of the supply lines for switching the loads on and off under the control of the switch means, the maximum number of load controllable by the system being the number of permutations of 2 from n.
 2. A vehicle electrical system, including a pair of electrical loads, a pair of switches controlling the loads respectively, a pair of feed lines, means whereby closing of one switch makes one feed line positive with respect to the other feed line, and closing of the other switch makes said one feed line negative with respect to the other feed line, and polarity sensitive switching means operable by a pulse between the feed lines for switching the loads on and off under the control of said switches, said switching means comprising a pair of latching relays successive actuations which energize and de-energize the respective loads, each relay having a coil connected across the feed lines, and the required polarity sensitivity being provided by a pair of diodes coupling the coils respectively to the feed lines. 